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Modified graphene/muscovite (MGMu) nanocomposite was synthesized with muscovite (Mu) and silane coupling agent modified graphene oxide through a simple hydrothermal method that exhibited excellent dispersion stability in oil. Compared with the base oil sample, the average friction coefficient and wear scar diameter of the MGMu oil sample decreased by 64.4 and 20.0%, respectively, and the microhardness of its wear scar was increased by 16.1%. The MGMu showed better tribological performance than its individual component due to the synergetic effect between the two components. The lubrication mechanism was proposed according to the morphology, chemical composition, and microhardness of the surface of wear scars. MGMu as an oil additive could fill between the friction pairs, cling to some asperities, and occur relative sliding between unit layers, thus playing a role in lubrication. It was found that MGMu would react with the surface of the friction pair during the friction process to generate Fe2O3, SiO2, SiC, and new aluminosilicate, which formed a self-repairing layer with high hardness. This chemically reactive film exhibited a lower shear strength, which made the oil sample containing MGMu have a lower coefficient of friction. [ABSTRACT FROM AUTHOR]

In this work, a sensor for quantitative detection of uric acid (UA) is successfully prepared by electrodepositing Nickel–Copper (Ni–Cu) alloy nanoparticles on poly (3,4-ethyldioxythiophene) modified nitrogen-containing grapheme (Ni–Cu/PEDOT/NGE). The anchoring of PEDOT and Cu–Ni alloy nanoparticles on NGE not only prevents the agglomeration of NGE, but also improves the catalytic activity of the composites. Ni–Cu/PEDOT/NGE shows high electrochemical performance to UA and the oxidation of UA on its interface was an action with two protons and two electrons. Under the optimized condition, the response current of the sensor is linear with UA concentration within the range of 0.1–10 μ M and 10–50 μ M. A low detection limit of 0.059 μ M at S/ N = 3 is obtained. Additionally, the fabricated electrochemical sensor with good sensitivity and selectivity to UA may be promising for practical clinical testing. Poly(3,4-ethylenedioxythiophene) and nickel–copper alloy nanoparticles are modified on nitrogen-doped graphene via electropolymerization and electrodeposition (Ni–Cu/PEDOT/NGE). The oxidation of uric acid on the interface of Ni–Cu/PEDOT/NGE is an action with two protons and two electrons. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor based on nitrogen doped graphene (NGE) and palygorskite (Pal) for the simultaneous detection of hydroquinone (HQ) and catechol (CT) has been proposed. Pal is particularly pointed out for its appreciable specific surface area and reactive-OH groups on its surface. Acid treatment Pal demonstrated better physico-chemical properties, which are propitious to electrochemical sensor construction. The introduction of NGE not only improved the poor conductivity of Pal but also served as an excellent adherent matrix. The modified electrode demonstrated the enhanced redox peak currents of HQ and CT with good discrimination. Under optimized conditions, the linear ranges for HQ and CT were 2–50 μM and 1–50 μM, with detection limit (LOD) of 0.8 μM and 0.13 μM, respectively. The result designates that the Pal/NGE composite promises to be a new eco-friendly modified material for sensor fabrication. [ABSTRACT FROM AUTHOR]

Epoxy-based composites containing montmorillonite (MMT) modified by silylation reaction with γ-aminopropyltriethoxysilane (γ-APTES) and 3-(glycidyloxypropyl) trimethoxysilane (GPTMS) are successfully prepared. The effects of filler loading and surface modification on the electrical and thermal properties of the epoxy/MMT composites are investigated. Compared with the pure epoxy resin, the epoxy/MMT composite, whether MMT is surface-treated or not, shows low dielectric permittivity, low dielectric loss, and enhanced dielectric strength. The MMT in the epoxy/MMT composite also influences the thermal properties of the composite by improving the thermal conductivity and stability. Surface functionalization of MMT not only conduces to the better dispersion of the nanoparticles, but also significantly affects the electric and thermal properties of the hybrid by influencing the interfaces between MMT and epoxy resin. Improved interfaces are good for enhancing the electric and thermal properties of nanocomposites. What is more, the MMT modified with GPTMS rather than γ-APTES is found to have greater influence on improving the interface between the MMT filler and polymer matrices, thus resulting in lower dielectric loss, lower electric conductivity, higher breakdown strength, lower thermal conductivity, and higher thermal stability. [ABSTRACT FROM AUTHOR]

Tin-based metal oxides usually suffer from severe capacity fading resulting from aggregation and considerable volume variation during the charge/discharge process in lithium ion batteries. In this work, a novel nanocomposite (MTO/N-RGO) of hollow amorphous MnSnO 3 (MTO) nanoparticles and nitrogen-doped reduced graphene oxide (N-RGO) has been designed and synthesized by a two-step method. Firstly, the nitrogen-doped graphene nanocomposite (MTO/N-RGO-P) with MnSn(OH) 6 crystal nanoparticles was synthesized by a facile solvothermal method. Subsequently, the MTO/N-RGO nanocomposite was obtained through the post heat treatment of MTO/N-RGO-P. The designed heterostructure and well-combination of the hollow amorphous MTO and N-RGO matrix can accelerate the ionic and electronic transport, and simultaneously accommodate the aggregation and volume variation of MTO nanoparticles during the lithiation–delithiation cycles. The as-prepared hybrid of MTO and N-RGO (MTO/N-RGO) exhibits a high reversible capacity of 707 mAh g −1 after 110 cycles at 200 mA g −1 , superior rate capability, and long-term cyclic life with high capacity of 610 mAh g −1 over 1000 cycles at 400 mA g −1 . Superior capacity retention of 97.3% over 1000 cycles was obtained. This work opens new opportunities to fabricate the high-performance electrode materials with heterostructure for lithium storage systems, especially for novel multi-metal oxide based nanocomposites with high cycling stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • The highly active crystal rod like Bi 2 O 3 /ZnO nanocomposite synthesized through a low cost coprecipitation method. • The modified electrode exhibits outstanding electrochemical performance towards the IP oxidation. • Bi 2 O 3 /ZnO/GCE exhibits good selectivity, stability, and reproducibility and good recovery for real sample analysis. With an increased understanding of human health in recent years, rapid and reliable methods for identifying prescription drugs have become progressively essential. In this concern, here we have demonstrated the nano crystal rod like Bi 2 O 3 /ZnO were first synthesized through a coprecipitation approach using sodium hydroxide as a precipitating agent. The prepared material was employed as an effective catalyst and then used to detect β adrenoceptor agonist isoprenaline (IP). Taking full advantage of about their improved properties, a novel electrochemical IP sensor was constructed by drop-coasting Bi 2 O 3 /ZnO on glassy carbon electrode. Various analytical and electrochemical methods were used to characterize the physical and chemical properties of prepared material. Under optimal conditions, the present sensor showed a dynamic linear range (0.04 µM to 258.4 µM) with a detection limit of 0.06 µM (n = 3). The sensitivity was calculated to be 11.45 μA μM−1 cm−2. Finally, the proposed electrode was successfully applied to the determination of IP in practical samples such as pharmaceutical and urine using standard addition method with satisfactory recovery result. [ABSTRACT FROM AUTHOR]

SnO 2 /NiFe 2 O 4 /Graphene (SNG) nanocomposites have been fabricated by a one-step hydrothermal synthesis method for Lithium ion batteries. Due to the synergetic effect between graphene, NiFe 2 O 4 and SnO 2 nanoparticle, the nanocomposites show good electrochemical performance. It is found that the electrochemical performance was enhanced with increasing content of SnO 2. Typically, the nanocomposite with 50 wt% SnO 2 exhibits a high reversible capacity of 731.5 mA h/g at a current density of 200 mA/g after 50 cycles, which can remain 80.9% of the first cycle. The material also exhibits a relatively high discharge capacity of 613 mA h/g at 800 mA/g after 100 cycles. These improved electrochemical performances are attributed to the capacity of NiFe 2 O 4 /SnO 2 and the SnO 2 buffer layers impede the pulverization of electrode material during lithium insertion/extraction. Furthermore, graphene sheet can enhance electrical conductivity and accommodate the volume change in some extent, which can keep the structure integrate, and then improving the cycling stability and rate capability. SnO 2 /NiFe 2 O 4 /Graphene (SNG) nanocomposites are fabricated by one-step hydrothermal method and the materials are utilized as anode material for high-performance Lithium ion batteries. Image 1 • One step hydrothermal synthesis of SnO 2 /NiFe 2 O 4 /Graphene for Lithium ion batteries. • NiFe 2 O 4 /SnO 2 contributes to the high capacity of SnO 2 /NiFe 2 O 4 /Graphene. • SnO 2 has cushioning effect on the insertion and release of lithium ions. • Graphene provides high surface to slow down the volume change. [ABSTRACT FROM AUTHOR]